G-20 Term of the Day: Kettling (verb) Also known as containment or corralling. Kettling is a police tactic for the management of large crowds during demonstrations or protests. It involves the formation of large cordons of police officers who then move to contain a crowd within a limited area. Protesters are prevented from leaving the area for several hours; as a result, detainees can be denied access to food, water and toilet facilities for a long period. The ostensible aim is to leave would-be violent protesters too tired to do anything but want to go home.